1. Technical Field
The present invention pertains to the field of network fault management tools. More particularly, the present invention concerns reporting to a user the status of components of a wide area network.
2. Prior Art
A propagation scheme is a method used by a network to indicate to a user information about the status of elements of the network, enabling the user to locate the source of a network malfunction. A propagation scheme developed by Hewlett Packard is accomplished by the Hewlett Packard Open View (HPOV) process called the Network Node Manager, version 3.31, which runs in the HPOV environment. The propagation scheme carried out by this HPOV process, called here the standard HPOV propagation scheme, is intended for use in a transmission control program/internet protocol (TCP/IP) network. Any HPOV propagation scheme, i.e. any propagation scheme running under HPOV, assumes that elements of the network exchange status information according to a simple network management protocol (SNMP).
HPOV is a configuration, performance, and fault management application for multivendor TCP/IP networks; it performs many functions. For example, it automatically discovers what devices are on the network and monitors their status. It automatically draws network maps and submaps based on the discovered devices, and places the discovered devices in one or another submap, based on topology. A network submap represents the physical topology of the network at the level of network segments (subnetworks) and gateways (routers), repeaters, multiport repeaters (hubs), and bridges that are attached to those segments.
The standard HPOV propagation scheme works well for Local Area Networks (LANs), but does not work very well for wide area networks. Its upward propagation scheme can incorrectly report interface level status at the equipment level (i.e. a problem at the physical line level is reflected in the status of the node). In addition, the standard HPOV propagation scheme does not downward propagate. Without downward propagation, an operator cannot determine that a sub-component is out-of-service purely because a component at an upper level has malfunctioned.
What is needed is a propagation scheme more suitable for a wide area network, i.e., a kind of network that generally has more complex equipment and connection hierarchies and is more geographically dispersed than a LAN, and in which connections are maintained separately from the other equipment. In particular, what is needed is an HPOV propagation scheme that does not report status problems at higher levels than is accurate.